Birmingham Crown Court heard that the couple had ‘spun a web of lies’ to hide how the defenceless tot met his death at their home in Denshaw Road in June 2011.

Rachel Brand QC, for the prosecution, described the attacks as “discreet incidents” which came about after sudden losses of temper from electrician Lewis on May 28 and then on June 19.

The toddler was left with Lewis on the evening of May 28 when his mum had popped out to the shops.

Lewis called in ambulance crews at around 5.15pm and told them the toddler had fallen and banged his head whilst he was trying to teach him to walk.

In fact, the thug had lost his temper with the little boy and slammed him into the floor.

Referring to a written admission from Lewis, Ms Brand said: “Mr Lewis said he was trying to help Kieron to walk but became frustrated at the lack of progress.

“He said he held Kieron, facing away from him, under his arms and swung him around quickly and slammed him down on the ground with his legs locked underneath.”

Birmingham Children's Hospital

After his death it was discovered the toddler suffered two fractures of his spine and bleeds in both eyes and brain in the attack.

Yet doctors at Birmingham Children’s Hospital failed to spot the injuries and he was discharged early at the request of his mum.

She would later lie to police telling officers she had been present during Kieron’s fall, in the “genuine belief” Lewis had nothing to do with the injuries, according to her barrister Kristina Montgomery QC.

The toddler continued to vomit and was in extreme pain in the days that followed and he was taken back to the hospital between May 28 and 30.

Barley, in mitigation, claimed that medics later diagnosed him as having gastrointestinal problems.

Yet she did not tell a health visitor on June 9 about his problems or the earlier incident and instead claimed her son was “recovering from a vomiting bug.”

The family had been on a day out on June 19 but when they returned home Kieron wet his nappy. What followed led to his death.

Ms Brand said: “He (Lewis) took Kieron to the bedroom to change him, while he asked Louise to run a bath.

“Kieron was crying and Lewis lost his temper in the bedroom. He shook Kieron causing the child’s head to move rapidly back and forth.

“He then threw Kieron into the cot, causing his head to hit the railing.”

Barley, who was not in the room at the time, dialled 999, telling the call handler she did not know what had happened.

Kieron was resuscitated and spent several days in intensive care but his life support was removed on June 23.

Andrew Lockhart QC, for Lewis, said he had been suffering with alcohol issues and a serious cocaine addiction at the time of the attacks.

As Lewis wept in the dock Mr Lockhart added: “He hates himself for what he did and thinks about this day in and day out. He feels nothing but shame of those momentary and dreadful lapses.”

Kristine Montgomery QC, for Barley, said: “Until Lewis entered his guilty pleas she did not believe that he had harmed Kieron.

“Those two instance are in direct contrast to how he acted and behaved with Kieron in front of her. This is not a case of her trying to protect him, or turning a blind eye. She has been punished with the loss of her son.

“People in the community judge her harshly and will continue to do so for the rest of her life.”

Judge William Davis told Lewis: “I am asked to consider you are now remorseful and contrite, but I have difficulty in accepting that proposition.

“This all happened in 2011 and since then you have lied to the police, family court judges and even to your own lawyers. You are plainly very sorry but you are not suffering from remorse in the true sense of the word.”

Lewis and Barley were first questioned by police before being charged in June 2013. They had denied the charges against them, and only changed their pleas as a trial approached in February.

Detective Chief Inspector Dawn Miskella, from the force public protection unit, said: after the sentencing: “Kieron was sadly let down by those who should have been caring for him.

“His mother and her partner spun a web of lies to conceal the truth of how Kieron came by his injuries and failed to seek further medical attention following the initial assault.

“However, almost three years on from the incidents Louise and Craig have finally admitted their crimes and have been jailed.

“We hope that the result can provide some closure for those who truly did care for young Kieron and are pleased that justice has been done.”